The Labour Party has caught out another Conservative politician trying to cheekily sign up to vote in its leadership election.

According to the party, Martin Callanan, a Tory peer who was a MEP and leader of the Tory MEP group, has been busted trying to get a sneaky vote in the race.

Conservatives have been having fun trying to sign up as registered supporters in order to vote for leftwinger Jeremy Corbyn. Yesterday Tory MP Tim Laughton was caught trying to do the same thing.

Ed Miliband changed the rules to allow members of the public to vote in Labour leadership races if they pay just £3 and say they agree with Labour values.

Labour will be keeping Callanan's £3 but he will not be allowed to vote. A Labour source said: "We are delighted that yet another senior Tory has decided he supports Labour’s aims and values. However, Lord Callanan will no doubt be very disappointed to hear that our robust procedures have caught him out, so he won’t be voting in our leadership election. We are very grateful for his kind donation to the Labour Party’s coffers."

Loughton said he made no attempt to hide his intent, writing in his application that he wanted to vote "Jeremy Corbyn and consign Labour to oblivion for a generation".

Tories believe Corbyn will be much easier to beat in 2020 than his more centrist rivals Andy Burnham, Yvette Cooper and Liz Kendall.

Some Labour MPs have also expressed fears of so-called "entryism" by militant left-wing activists into the party to back Corbyn, the surprise front-runner, who is opposed to austerity and wants public services re-nationalised. Corbyn himself has insisted that only people who support Labour should sign up to vote in the contest.